1. Technical Field
The present invention relates to a stop lamp lighting control device for an electric vehicle having an electric regenerative braking system which controls stop lamps of the electric vehicle to be suitably turned on or off.
2. Related Art
In electric vehicles, such as electric vehicle, hybrid vehicles, or plug-in hybrid vehicles, an electromotor (motor) is used as a driving source. In such electric vehicles, one is known in which an electric regenerative braking system is provided as an assistant brake.
The electric regenerative braking system is configured so that when a driver stops operating an accelerator pedal and thus an accelerator opening degree becomes a frilly closed state, circuit switching is performed so that the motor is rotated by a driving force of wheels and thus severs as a generator, thereby generating a braking force (e.g., see JP-A-2012-153294). As electric power generated by regenerative braking is charged to a battery.
According to the pre-revised regulation notified from the Ministry of Land, Infrastructure and Transport of Japan, when the electric regenerative braking system, which is adapted to be activated as an accelerator operation device is released, is being operated, turn-on of brake lamps and the like is prohibited even at any deceleration.
However, the regulation is revised so that turn-on of brake lamps and the like is obligated when a deceleration exceeds a predetermined specific value.
Relationships between decelerations and turn-on requirements are as follows:
(1) If the deceleration is −0.7 m/s2 or less: turn-on prohibition
(2) If the deceleration exceeds −0.7 m/s2 and −1.3 m/s2 or less: optionally turn-on
(3) If the deceleration exceeds −1.3 m/s2: obligatory turn-on
The revised regulation is applied to automobiles which are newly subjected to designation of type or the like since Jan. 30, 2014.
FIG. 3 shows the revised regulation, in which a horizontal axis represents vehicle speeds and a vertical axis represents decelerations. In FIG. 3, a ‘second deceleration threshold value for turning off the stop lamp’ corresponds to ‘−0.7 m/s2’ and a ‘first deceleration threshold value for turning on the stop lamp’ corresponds to ‘−1.3 m/s2’.
Herein, a minus sign ‘−’ is assigned to values of decelerations, and when magnitudes of decelerations are compared, a deceleration having a higher absolute value is referred to as a higher deceleration. For example, a deceleration of 1.3 m/s2 is referred to as a higher deceleration, as compared to a deceleration of −0.7 m/s2 
Correspondingly, for regenerative torques as described below, a minus sign ‘−’ is assigned to values of regenerative torques, and when magnitudes of regenerative torques are compared, a regenerative torque having a higher absolute value is referred to as a higher regenerative torque. For example, a regenerative torque of −60 Nm is referred to as a higher regenerative torque, as compared to a regenerative torque of −20 Nm.
A weight of a vehicle greatly influences a deceleration of the vehicle. Accordingly, what is required is to perform suitable turn-on or turn-off control to conform to the revised regulation (see FIG. 3) while considering a weight of a vehicle.
The present invention has been made keeping in mind the above problems, and an object thereof is to provide a stop lamp lighting control device for an electric vehicle, in which turn-on or turn off control of brake lamps stop lamps) can be performed to suitably alert sufficient attention to a succeeding vehicle while observing the revised regulation.